Management of the short-bowel syndrome

Concise review on short bowel syndrome: Etiology, pathophysiology, and management

Adults have approximately 20 feet of small intestine, which is the primary site for absorbing essential nutrients and water. Resection of the intestine for any medical reason may result in short bowel syndrome (SBS), leading to loss of major absorptive surface area and resulting in various malabsorption and motility disorders. The mainstay of treatment is personalized close dietary management. Here we present SBS with its pathophysiology and different nutritional management options available. The central perspective of this paper is to provide a concise review of SBS and the treatment options available, along with how proper nutrition can solve major dietary issues in SBS and help patients recover faster.

Severe Short Bowel Syndrome: Prognosis for Nutritional Independence Through Management by a Multidisciplinary Nutrition Service and Surgery

INTRODUCTION

Short bowel syndrome (SBS) is a debilitating condition associated with significant morbidity and mortality. Historically, SBS patients require indefinite parenteral nutrition (PN) and endure lifelong nutritional challenges. The purpose of this study was to review the outcomes, specifically nutritional independence, of a multidisciplinary nutrition service.

METHODS

A retrospective analysis of SBS patients followed by our surgical nutrition service was performed. Patients without 1-year follow-up were excluded. Demographics and nutritional parameters were collected at 4 intervals: initial presentation, 1-year, 2-year, and 5-year follow-up. Short bowel syndrome anatomical subtypes identified through operative reports were characterized as end jejunostomy, jejunocolonic, or jejuno-ileocolonic with ileo-cecal valve intact. Intestinal failure was defined by the requirement of PN, while intestinal insufficiency was defined by enteral support requirement. Clinical outcomes examined included mortality, fistula closure, and nutritional independence.

RESULTS

The study cohort comprised 89 patients, 50 of whom had ≤ 100 cm intestinal length. Mean age was 57 ± 17y, 55 (62%) were female, and median initial intestinal length was 77 [60-120] cm. Short bowel syndrome was complicated by fistulas in 47 (53%) of patients. Overall mortality was 13%, and 67 (75%) were liberated from PN. A total of 58 (65%) underwent operative intervention and fistula closure was achieved in 37 of 47 (79%) patients.

CONCLUSIONS

Short bowel syndrome patients can experience significant benefit under treatment by a multidisciplinary nutrition service. By incorporating surgical intervention, the majority of patients previously relegated to lifelong PN have the opportunity to become nutritionally independent within 5 years.

Short Bowel Syndrome: Clinical Guidelines for Nutrition Management

Intestinal failure is a condition in which inadequate digestion or absorption of fluid, electrolytes, and nutrients leads to dehydration or malnutrition. The most common cause of intestinal failure is short bowel syndrome (SBS) defined as <200 cm of functional small intestine. SBS may result from congenital abnormalities or from surgical resection. For the past 3 decades, patients with severe SBS were managed with home parenteral nutrition (HPN). With the emergence of new therapies, the clinician now has multiple options to treat these patients. These include intestinal rehabilitation regimens whereby patients are treated with specialized oral diets, soluble fiber, oral rehydration solutions (ORS), and trophic factors to enhance absorption. There are also a variety of surgical techniques available to preserve intestinal length. Small bowel and multivisceral transplantation has evolved during the last decade to be a valid therapeutic option for those patients who cannot be rehabilitated or who fail HPN. These are interrelated services designed to offer the patient the best therapeutic options to meet their individual needs. This article reviews the principles associated with the nutrition management of this very complex and diverse group of patients.

Estudo morfológico do intestino de ratos após a criação cirúrgica de esfíncteres artificiais

OBJETIVO: Avaliar as alterações morfológicas ocorridas após à confecção de esfíncteres no intestino delgado de ratos. MÉTODO: Foram estudados 30 ratos, Wistar, distribuídos em três grupos de 10 animais. Grupo A, controle, foi retirado um segmento de intestino delgado de 20mm de extensão. Grupo B, foram realizados dois esfíncteres, um a 100mm e outro a 150mm da junção íleo-cecal. Grupo C, um esfíncter à 100mm da junção íleo-ceco-cólica. Entre 10º e 14º dia os animais do Grupo B e C foram re-operados para a ressecção do segmento intestinal envolvendo os esfíncteres com margem de 10mm proximal e distal. As aferições de peso foram feitas no pré-operatório das duas intervenções. O diâmetro das alças foi computado antes e depois da confecção dos esfíncteres. Nas peças ressecadas dos três grupos foram medidas as alturas das vilosidades dos segmentos pré e pós-esfíncter dos Grupos B e C, segmento intermediário do Grupo B e segmento intestinal do Grupo A. Os dados obtidos foram submetidos à análise estatística do programa SPSS. RESULTADO: O peso dos animais aumentou nos dois grupos com significância no grupo B. Aumento do diâmetro das alças e a média das alturas das vilosidades foram significante. CONCLUSÃO: A confecção dos esfíncteres leva a alterações da camada de vilos e dos diâmetros das alças, semelhantes àquelas que ocorrem na fase de adaptação intestinal após ressecções.

Treatment of adult short bowel syndrome with recombinant human growth hormone: a review of clinical studies

Extensive resection of the intestinal tract frequently results in inadequate digestion and/or absorption of nutrients, a condition known as short bowel syndrome (SBS). Several therapies, including parenteral nutrition (PN), bowel rehabilitation, and surgical procedures to reconstruct the bowel, have been used for patients with SBS. However, these treatments only partially correct the underlying problem of reduced bowel function in some patients. This review investigates the results of studies of recombinant human growth hormone (r-hGH) in patients with SBS. In one randomized, controlled and five open-label studies, treatment with r-hGH significantly increased absorption of energy, protein and/or carbohydrates. Four studies also demonstrated significantly increased body weight, lean body mass, total body potassium and/or total body water in response to r-hGH. However, in two other randomized controlled trials, r-hGH had no significant effect on energy or fluid absorption. In one randomized, controlled study and six open-label trials, treatment with r-hGH also allowed a majority of patients, including those with no colon and significant bowel resection, to eliminate or substantially reduce PN. Optimal clinical benefits appear to be achieved when r-hGH is administered in combination with a specialized oral diet and perhaps with glutamine. Although the use of r-hGH to treat SBS patients remains controversial, results from these studies suggest that short-term r-hGH treatment in combination with optimized medical and dietetic treatments can enhance bowel absorption and function and, with the continuation of optimized medical and dietetic treatments, may reduce PN requirements for a wide range of patients with SBS.

ESPEN Guidelines on Enteral Nutrition: Gastroenterology

Undernutrition as well as specific nutrient deficiencies have been described in patients with Crohn's disease (CD), ulcerative colitis (UC) and short bowel syndrome (SBS). The present guideline gives evidence-based recommendations for the indication, application and type of formula of enteral nutrition (EN) (oral nutritional supplements (ONS) or tube feeding (TF)) in these patients. It was developed in an interdisciplinary consensus-based process in accordance with officially accepted standards and is based on all relevant publications since 1985. ONS and/or TF in addition to normal food is indicated in undernourished patients with CD or CU to improve nutritional status. In active CD EN is the first line therapy in children and should be used as sole therapy in adults mainly when treatment with corticosteroids is not feasible. No significant differences have been shown in the effects of free amino acid, peptide-based and whole protein formulae for TF. In remission ONS is recommended only in steroid dependent patients in CD. In patients with SBS TF should be introduced in the adaptation phase and should be changed with progressing adaptation to ONS in addition to normal food.

Extensive small bowel resection in dogs and cats: 20 cases (1998–2004)

OBJECTIVE

To determine outcome in dogs and cats that underwent extensive (ie, > 50%) resection of the small intestine and identify factors associated with outcome.

DESIGN

Retrospective case series.

ANIMALS

13 dogs and 7 cats.

PROCEDURE

Medical records were reviewed, and follow-up information was obtained.

RESULTS

In all 7 cats and in 8 of the 13 dogs, extensive intestinal resection was performed because of a foreign body. Mean+/-SD estimated percentage of intestine that was removed was 68+/-14% (range, 50% to 90%). Two dogs were euthanized 3 days after surgery because of dehiscence of the surgical site and development of septic peritonitis; 1 dog died of acute respiratory distress syndrome 5 days after surgery. The remaining 10 dogs and 7 cats were discharged from the hospital, and follow-up information was available for 15 of the 17. Median survival time was 828 days, and 12 of the 15 animals for which long-term follow-up information was available had good outcomes. However, none of the factors examined, including percentage of intestine resected, were significantly associated with outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Most dogs and cats that underwent extensive resection of the small intestine had a good outcome. The amount of intestine resected was not associated with outcome. These data may be useful in providing prognostic information in cases of extensive small intestinal resection.

Glutamine alone or combined with short-chain fatty acids fails to enhance gut adaptation after massive enterectomy in rats

PURPOSE: To investigate the effect of oral glutamine alone or combined with short chain fatty acids (SCFA) in the intestinal adaptation of rats submitted to an massive enterectomy. METHODS: After receiving 70% small bowel resection, 30 Wistar rats were randomized to received either standard rat chow (control group, n=10) or the same diet supplemented with 3,05% of glutamine alone (glutamine group, n=10) or combined with a solution containing SCFA (glutamine+SCFA group, n=10). Animals were killed on the 14th postoperative day. Mucosal weight, crypt depth, villus height, wall width, and the mucosal content of DNA, were assessed in basal conditions (resected gut specimen) and compared to the small bowel specimen collected on the postoperative day 14, at both jejunum and ileum sites. RESULTS: All groups presented similar pattern in weight evolution. In all groups, both the morphological findings and the DNA content were significantly higher at the end of the experiment than in basal conditions, at both the jejunum and ileum. Except for the jejunum wall width that was higher in control group (808±95 µ) than in the other two groups (glutamine = 649±88 µ and glutamine+SCFA = 656±92; p<0.01), there was no difference among them in all variables at both intestinal sites after 14 days. CONCLUSION: All groups presented adaptation of the intestinal mucosa in the remnant gut. Glutamine combined or not with short chain fatty acids fails to influence the adaptive response of the small bowel.

Weight loss and morphometric study of intestinal mucosa in rats after massive intestinal resection: influence of a glutamine-enriched diet

Short-bowel syndrome is responsible for significant metabolic alterations that compromise nutritional status. Glutamine is considered an essential nutrient for enterocytes, so beneficial effects from supplementation of the diet with glutamine are hypothesized.

PURPOSE

In this study, the effect of a diet enriched with glutamine was evaluated in rats undergoing extensive small bowel resection, with analysis of postoperative weight loss and intestinal morphometrics of villi height, crypt depth, and thickness of the duodenal and remnant jejunal mucosa.

METHODS

Three groups of male Wistar rats were established receiving the following diets: with glutamine, without glutamine, and the standard diet of laboratory ration. All animals underwent an extensive small bowel resection, including the ileocecal valve, leaving a remnant jejunum of only 25 cm from the pylorus that was anastomosed lateral-laterally to the ascendant colon. The animals were weighed at the beginning and end of the experiment (20th postoperative day). Then they were killed and the remnant intestine was removed. Fragments of duodenal and jejunal mucosa were collected from the remnant intestine and submitted to histopathologic exam. The morphometric study of the intestinal mucosa was accomplished using a digital system (KS 300) connected to an optic microscope. Morphometrics included villi height, crypt depth, and the total thickness of intestinal mucosa.

RESULTS

The weight loss comparison among the 3 groups showed no significant loss difference. The morphometric studies showed significantly taller duodenal villi in the glutamine group in comparison to the without glutamine group, but not different from the standard diet group. The measurements obtained comparing the 3 groups for villi height, crypt depth, and thickness of the remnant jejunum mucosa were greater in the glutamine-enriched diet group than for the without-glutamine diet group, though not significantly different from with standard-diet group.

CONCLUSIONS

In rats with experimentally produced short-bowel syndrome, glutamine-enrichment of an isonitrogenous test diet was associated with an improved adaptation response by the intestinal mucosa but not reduced weight loss. However, the adaptation response in the group receiving the glutamine-enriched diet was not improved over that for the group fed regular chow.

Classification, epidemiology and aetiology

Intestinal failure and its most important cause, short-bowel syndrome (SBS), are rare clinical entities leading to a vast complex of symptoms and complications with significant morbidity and mortality. Both conditions occur as the result of a massive reduction in enteral nutrient absorptive capacity. Disease manifestation is based on aetiological and anatomical characteristics such as remaining intestinal length and the presence of a functionally intact colon. Congenital and perinatal conditions, for example, intestinal atresia, necrotizing enterocolitis (NEC) and intestinal volvulus are the most important causes in children. The aetiology in adults is based on diseases inducing loss of intestinal function or loss of intestinal surface area after extensive surgical resections. The most frequent causes are mesenteric infarction, radiation enteritis and Crohn's disease. Knowledge of the epidemiology of intestinal failure and SBS is limited, being mainly based on the extrapolated figures of home parenteral nutrition centres and single-centre studies. At present, the incidence of SBS is estimated to be 2-5 per million.

Influência da glutamina na mucosa do instestino de ratos submetidos à enterectomia extensa

OBJETIVO: Avaliar a influência de uma dieta suplementada com glutamina sobre as alterações adaptativas no intestino delgado de ratos com enterectomia extensa. MÉTODO: Vinte ratos Wistar, divididos aleatoriamente em dois grupos de dez animais, foram enterectomizados e alimentados com dois tipos diferentes de dieta nos 14 dias de pós-operatório: grupo controle (GC)-dieta padrão; grupo glutamina (GG)-dietapadrão acrescida de 3,05% de glutamina. Avaliou-se evolução ponderal, peso da mucosa intestinal (PM), profundidade das criptas (PC), altura das vilosidades (AV), espessura da parede (EP) e o conteúdo de ácido desoxirribonucléico (DNA) na mucosa intestinal, no início e no final do experimento. RESULTADOS: Com exceção da PC ileal do Grupo GG, todas as variáveis estudadas tiveram um aumento significativo em seus valores finais tanto no jejuno quanto no íleo (p<0,05).Entre os grupos, a comparação do PM, AV, DNA da mucosa, no jejuno e no íleo, tanto inicialmente quanto no final do estudo, bem como da EP inicial no jejuno e íleo eda PC no jejuno final e no íleo inicial e final não mostraram diferenças significativas (p>0,05). No jejuno inicial, a PC no grupo GC foi maior (p=0,005). A EP do jejuno e íleo final foi maior no grupo GC. CONCLUSÃO: A suplementação dietética com a glutamina não melhorou as alterações adaptativas que ocorrem no remanescente intestinal.

Indications for specific therapy in the rehabilitation of patients with the short-bowel syndrome

Diarrhoea, malabsorption and malnutrition characterize the short-bowel syndrome. Following the initial intestinal resection, complications such as fistulas and intra-abdominal abscesses may occur, but these usually resolve with appropriate surgical care. All residual intestine should be placed in continuity before serious attempts at rehabilitation with oral feedings are initiated. Small hourly oral feedings composed of food items high in complex carbohydrate and low in fat are started when appropriate and the diet is gradually increased as intestinal adaptation occurs. The goal during this process is to prevent diarrhoea and allow the formation of semiformed stools. With time, parenteral nutrition (PN) can be reduced, and the time required depends on both length of residual bowel and the particular anatomy involved-for example, the presence or absence of the colon. A programme of optimal diet plus growth hormone (0.1 mg/kg) and oral glutamine (30 g/day) enhances the adaptive process and allows many patients independence from PN. However, those with extremely short segments of jejuno-ileum (<50 cm) and no colon have excessive fluid and electrolyte losses, and intestinal transplantation may be the only therapy which allows such patients to be independent of PN.

Glucagon-Like Peptide-2 and Short-Chain Fatty Acids: A New Twist to an Old Story

The nutritional regulation of intestinal adaptation extends beyond the route of nutrient administration as specific nutrients are known to mediate the adaptive response. Dietary carbohydrates are known to enhance intestinal adaptation in patients with short-bowel syndrome. This review discusses SCFA-induced adaptation in intestinal structure and function in adult rat and neonatal piglet models. Potential mechanisms relate to the salvage of energy as SCFA in the colon, direct mediation of intestinal adaptation by SCFA and stimulated release of glucagon-like peptide-2 (GLP-2) from enteroendocrine L cells by SCFA. Among the produced SCFA, butyrate appears to be responsible for increasing plasma GLP-2 concentration, in addition to the enterotrophic effects. Emerging evidence reveals that physiological concentrations of butyrate acutely upregulate the expression of key enterocyte-associated nutrient transporters. Focused experiments are needed to carefully identify the critical components of intestinal adaptation and yield conclusions regarding the relative contributions of SCFA and GLP-2 during the various phases of this process.

The anabolic effects of recombinant human growth hormone and glutamine on parenterally fed, short bowel rats

AIM: To evaluate the metabolic effects associated with administration of rhGH and/or Gln in parenterally fed, short-bowel rats.

METHODS: Forty SD rats subjected to 75% intestinal resection and maintained with parenteral nutrition were randomly divided into 4 groups as follows: -rhGH, -Gln; -rhGH, +Gln; +rhGH, -Gln; +rhGH, +Gln. Body weight and nitrogen balance were evaluated daily. After 6 d of PN, rats were killed, various organs were dissected and weighted, the carcasses were used for analysis of body composition. Serum GH and IGF-1 were determined by RIA method.

RESULTS: Weight loss in rats with rhGH (17.4 ± 12.8 g) and rhGH+Gln (23.8 ± 3.5 g) was significantly less than rats with PN alone (29.6 ± 6.9 g) and rats with Gln-supplemented PN (31.85 ± 12.8 g), P < 0.05. The accumulated NB in rats with rhGH (1252.9 ± 294.3 mg N/d) and rhGH+Gln (1261.7 ± 85.5 mg N/d) was significantly greater than those with PN alone (704.8 ± 379.0 mg N/d) and with Gln-supplemented PN (856.7 ± 284.4 mg N/d), P < 0.05. The absolute weight of gastrocnemius muscle in rats with rhGH (2683.9 ± 341.6 mg) and rhGH+Gln (2579.1 ± 359.5 mg) was greater than those with PN alone (2176.3 ± 167.1 mg) and with Gln-supplemented PN (2141.9 ± 353.6 mg). Although the absolute weight of remnant small intestine itself was not significantly different in 4 experimental groups, the weight/length of the segments was greater in rats with rhGH and/or Gln (48.7 ± 5.5, 52.7 ± 4.1 and 67.4 ± 5.3 respectively) than those with PN alone (47.8 ± 5.0), there were synergistic effects between rhGH and Gln in improvement of the weight/length of remnant small intestine, P < 0.05. Analyses of body carcass composition showed that a higher percentage of carcass weight as protein and a lower percentage of carcass weight as fat were occurred in rats with rhGH (20.8 ± 4.0, 6.0 ± 2.6) and rhGH+Gln (21.3 ± 2.4, 4.4 ± 1.5) than those with PN alone (16.4 ± 2.4, 9.2 ± 3.7) and with Gln-supplemented PN (17.8 ± 3.0, 6.3 ± 2.0), rhGH had significant effects on alteration of body composition, P < 0.05. Serum GH and IGF-1 concentration in rats with rhGH (5.221 ± 0.8 and 425.1 ± 19.2 ng/mL respectively) and rhGH+Gln (5.507 ± 1.0 and 461.1 ± 49.9 ng/mL respectively) were greater than those with PN alone (3.327 ± 1.7 and 325.8 ± 29.6 ng/mL respectively) and with Gln-supplemented PN (3.433 ± 0.1 and 347.7 ± 55.7 ng/mL respectively), P < 0.01.

CONCLUSION: rhGH significantly improves the anabolism in parenterally fed. Short bowel rats, anabolic effect with Gln is less dramatic, there is no synergistic effect between rhGH and Gln in improvement of whole body anabolism. IGF-1 plays an important part in growth-promoting effects of rhGH.

Intestinal adaptation in short bowel syndrome

Regaining enteral autonomy after extensive small bowel resection is dependent on intestinal adaptation. This adaptational process is characterized by hyperplastic growth of the remaining gut, which is accompanied by both an increase of cell division at the level of the crypt cells and by an increased rate of programmed cell death (apoptosis). Apart from the absorptive function, the small bowel also has a barrier function and plays an important role in interorgan metabolism. Also, these functions are greatly affected by a massive intestinal resection and subsequent recovery by intestinal adaptation. This review aims to give an overview of the debilitating effects of massive intestinal resection on gut function and subsequently discusses intestinal adaptation and possible factors stimulating adaptation.

Nutritional management of short bowel syndrome in adults

Short bowel syndrome (SBS) comprises the sequelae of nutrient, fluid, and weight loss that occurs subsequent to greatly reduced functional surface area of the small intestine. Signs and symptoms of SBS include electrolyte disturbances; deficiencies of calcium, magnesium, zinc, iron, vitamin B12, or fat-soluble vitamin deficiency; malabsorption of carbohydrates, lactose, and protein; metabolic acidosis, gastric acid hypersecretion; formation of cholesterol biliary calculi and renal oxalate calculi; and dehydration, steatorrhea, diarrhea, and weight loss. Thorough nutritional management is the key factor in achieving an optimal outcome in SBS. Total parenteral nutrition is necessary in the early stages, as is replacement of excess fluid and electrolyte losses. Nutritional management of SBS has traditionally been divided into three phases: an acute phase when total parenteral nutrition is usually begun, an adaptation phase, and a maintenance phase. Recommendations regarding the need for parenteral nutrition vary depending on the presence or absence of certain factors: the ileocecal valve, jejunum, and functional colon. Patients with residual small bowel length of 100 cm or less usually require the administration of parenteral nutrition at home with good results. The total parenteral nutrition diet should consist of a majority of calories from fat, followed by protein, and the remaining as carbohydrates. Vitamins, minerals, and trace elements should also be added accordingly. Although total parenteral nutrition is initially necessary, treatment goals should focus on early transition to enteral nutrition followed by oral feeds. Other recent advances in the medical management of SBS include pharmacologic treatment and the use of specific nutrients and growth factors to stimulate intestinal absorption and adaptation. Both animal studies and clinical trials in humans have shown much promise in supplementation with growth factors and hormones. This strategy is likely to play a greater role in the treatment of SBS in the future.

Nutritional complications and management of intestinal transplant

Advances in intestinal transplantation provide a promising alternative to patients with intestinal failure and chronic dependence on total parenteral nutrition. However, many physiologic complications arising from the surgical procedure and high-dose immunosuppression, along with potential for rejection and infection, make successful graft function after transplantation a challenge. Nutrition issues unique to this patient population include recovery of normal intestinal motility and absorptive capacity. Diarrhea and high stomal output, which are common postoperatively, lead to deficits in macronutrients and micronutrients, especially electrolytes. Impaired gastrointestinal function affects ability to wean patients off hyperalimentation and enable them to tolerate nutrients enterally. In pediatric recipients of intestinal transplant, lack of experience with food or prior food aversions can lead to refusal to eat after transplant--additional challenges to achieving oral intake. Early and aggressive nutrition intervention is necessary for resolution of nutritional deficits and health of donor small bowel. This article presents an overview of the surgical procedure of intestinal transplantation and describes the physiologic adaptations that occur after the process. A case study demonstrates the clinical and nutritional hurdles associated with an intestinal transplant in a child and how dietitians can provide nutrition management. The potential role of individual nutrients in recovery of the transplanted bowel is also discussed.

Small bowel adaptation is dependent on site of massive enterectomy

BACKGROUND

Changes in amino acid transport after massive enterectomy occur in a nutrient-dependent fashion and may affect long-term outcome. Epidermal growth factor (EGF) can enhance nutrient transport and a defective epidermal growth factor receptor (EGF-R) has been noted to attenuate adaptation. Most animal studies, however, have examined only a single site of resection. This does not mimic the clinical situation where disease dictates the site of resection leading to proximal, middle, or distal enterectomies. We hypothesize that the site of massive enterectomy will alter nutrient transport and EGF-R levels in the residual gut.

MATERIALS AND METHODS

New Zealand White rabbits were randomized to control, midgut division, or 70% resection (proximal, midgut, or distal). After 1 week, sodium-dependent transport of glucose, glutamine, alanine, and leucine into brush border membrane vesicles was quantitated. EGF-R protein was determined by Western blot analysis.

RESULTS

At baseline, amino acid transport was greater in ileum than jejunum. Surgery alone elevated glutamine and leucine jejunal transport by 130 and 97%, respectively, over controls (P < 0.05). Midgut resection increased jejunal glutamine transport 61% over control (P < 0.05). In contrast, distal resection increased jejunal alanine transport by 150% over controls with no change in glutamine (P < 0.05). After midgut resection, EGF-R was significantly greater (124%) in ileum then in jejunum in whole mucosa homogenates. Proximal resection significantly lowered ileal EGF-R compared to that seen in midgut resected residual ileum.

CONCLUSIONS

Site of massive resection is important in determining postoperative changes in nutrient transport and EGF-R.

Insulinlike growth factor 1 and insulinlike growth factor 3: indices of intestinal failure in children

BACKGROUND/PURPOSE

A number of pediatric patients with short bowel syndrome (SBS) manifest growth failure despite aggressive nutritional support. Exogenous growth hormone (GH) therapy in children with SBS has proved disappointing. The purpose of this study was to determine if there were characteristic patterns of GH, IGF-1, or IGFBP-3 levels in pediatric SBS patients with profound growth failure in an effort to elucidate an early strategic approach to management of SBS in the subpopulation.

METHODS

Forty patients (29 boys, 11 girls; mean age, 5.3 years; range, 0.5 to 18.6 years) with SBS (<30% total bowel length) who received intensive nutrition support and follow-up underwent serological tests for GH, IGF-1, IGFBP-3, and thyroid function. Height (HT), weight (WT), and bone age were assessed relative to age-appropriate percentiles. Growth failure was defined as a HT and WT at less than the fifth percentile and bone age > or = 2 standard deviations below actual age. Residual small bowel length was determined by review of pathological and operative reports. Comparisons between the growth factors, bowel length, and anthropometric data were analyzed by chi2.

RESULTS

Two distinct subgroups of patients emerged from our study. Thirty-eight percent of patients (n = 11) had growth failure by anthropometry that was associated significantly with low IGF-1 independently and with both IGF-1 and IGFBP-3 levels (P< 0.05). There were no significant associations with GH level, thyroid function, small bowel length, or the amount of parenteral versus enteral intake in either subgroup of these patients. Low IGF-1 and IGFBP-3 but not GH levels may be indices of intestinal failure in pediatric SBS. Growth in this subpopulation is refractory to aggressive standard approaches to nutritional support and may require early interventions.

CONCLUSION

Exogenous IGF-1 and IGFBP-3, not GH, may be beneficial to treat this subpopulation.

Regenerative signals for intestinal epithelial organoid units transplanted on biodegradable polymer scaffolds for tissue engineering of small intestine

BACKGROUND

Our laboratory is investigating the tissue engineering of small intestine using intestinal epithelial organoid units seeded onto highly porous biodegradable polymer tubes. This study investigated methods of stimulation for optimizing neointestinal regeneration.

METHODS

Intestinal epithelial organoid units harvested from neonatal Lewis rats were seeded onto porous biodegradable polymer tubes and implanted into the omentum of adult Lewis rats in the following groups: (1) the control group (group C), implantation alone (n=9); (2) the small bowel resection (SBr) group, after 75% SBr (n=9); (3) the portacaval shunt (PCS) group, after PCS (n=8); and (4) the partial hepatectomy (PH) group, after 75% PH (n=8). Neointestinal cyst size was recorded using ultrasonography. Constructs were harvested at 10 weeks and were examined using histology. Morphometric analysis of the neomucosa was obtained using a computer image analysis program (NIH Image, version 1.59).

RESULTS

Cyst development was noted in all animals. Cyst lengths and diameters were significantly larger in the SBr group at 7 and 10 weeks compared with the other three groups (P<0.05; analysis of variance [ANOVA], Fisher's protected least significant difference). Histology revealed a well-vascularized tissue with a neomucosa lining the lumen with invaginations resembling crypt-villus structures. Morphometric analysis demonstrated a significantly greater villus number, height, area, and mucosal surface in the SBr group compared with the other three groups and a significantly greater crypt number and area in the PCS group compared with group C (P<0.05; ANOVA, Fisher's protected least significant difference).

CONCLUSIONS

Intestinal epithelial organoid units transplanted on porous biodegradable polymer tubes can successfully vascularize, survive, and regenerate into complex tissue resembling small intestine. SBr and, to a lesser extent, PCS provide significant regenerative stimuli for the morphogenesis and differentiation of tissue-engineered small intestine.

Epidermal growth factor and human growth hormone induce two sodium-dependent arginine transport systems after massive enterectomy

BACKGROUND

A combination of epidermal growth factor (EGF) and human growth hormone (hGH) after massive enterectomy induces a 400% increase in arginine transport in the remnant distal small intestine. The kinetic mechanism(s) responsible for enhanced arginine transport under these conditions is unknown.

METHODS

New Zealand White rabbits underwent 70% midjejunoileal resection. After a 1-week recovery period, animals received hGH (0.2 mg/kg/d IM), EGF (1.5 microg/kg/h SC), hGH + EGF, or vehicle (equal volume) for 7 days. Transport of tritiated arginine into brush border membrane vesicles prepared from distal remnant small intestinal mucosa was quantified in the presence and absence of a sodium gradient over a range of arginine concentrations (25 to 5000 micromol/L).

RESULTS

Eadie-Hofstee transformation of the kinetic data demonstrates two sodium-dependent arginine transport systems, comprising a high-capacity, low-affinity system and a low-capacity, high-affinity system. A combination of EGF and hGH significantly upregulates both the high-capacity (685%) and low-capacity (350%) maximum transport velocity (Vmax). Additionally, EGF alone significantly upregulates Vmax by 200% in the low-capacity system. There were no significant changes in transport affinity (Km) in either system.

CONCLUSIONS

There are two quiescent sodium-dependent arginine transport systems in the distal small intestine. A combination of EGF and hGH after massive enterectomy increase arginine transport by Vmax upregulation in both the high-capacity/low-affinity and low-capacity/high-affinity systems.

Epidermal growth factor and human growth hormone accelerate adaptation after massive enterectomy in an additive, nutrient-dependent, and site-specific fashion

BACKGROUND

After massive enterectomy (ME), remnant intestine undergoes compensatory adaptation. Epidermal growth factor (EGF) and human growth hormone (hGH) have each been shown to enhance total length small intestine nutrient transport after ME. This study aims to determine the differential effects of EGF and hGH on proximal and distal small intestinal remnants after ME.

METHODS

New Zealand white rabbits underwent 70% mid-jejunoileal resection. After 1 week, animals received hGH (0.2 mg/kg/day), EGF (1.5 micrograms/kg/hr), hGH + EGF, or vehicle (equal volume) for 7 days. Sodium-dependent uptake of glucose, glutamine, alanine, leucine, and arginine into brush border membrane vesicles was quantitated. Serum insulin-like growth factor-I concentrations as well as proximal and distal villus and microvillus heights were measured. IGF binding protein-3 and -4 mRNA expression was determined in full-thickness proximal and distal gut remnants.

RESULTS

Concomitant hGH and EGF treatment up-regulates glucose (100%), glutamine (80%), and leucine (60%) transport in the proximal remnant; alanine (150%) and arginine (400%) transport in the distal remnant; and microvillus height (25% to 35%) both proximally and distally. Serum IGF-I levels and gross villus heights were not different among groups.

CONCLUSIONS

Co-infusion of hGH and EGF accelerates intestinal adaptation after ME in an additive, nutrient-dependent, and site-specific fashion via enhanced nutrient transport as well as microvillus hypertrophy.

Factors predicting a successful outcome after pharmacologic bowel compensation

OBJECTIVES

The authors determined those factors that predict a successful outcome in patients who receive pharmacologic agents to promote bowel absorption after massive intestinal resection.

SUMMARY BACKGROUND DATA

Patients with the short bowel syndrome are maintained on long-term total parenteral nutrition (TPN) or more frequently considered for intestinal transplantation as part of their treatment program. The authors have administered a combination of trophic agents and a specialized diet to further enhance intestinal compensation and optimize nutrient absorption in patients with intestinal failure.

METHODS

Forty-five TPN-dependent adults with a jejunal-ileal remnant < or = 50 cm and a portion of colon in continuity were treated with growth hormone, glutamine, and a modified diet for 4 weeks and observed for an average of 1.8 years.

RESULTS

The average age of the patients was 43 years, the average jejunal-ileal length was 23 cm, and the average length of time the patient received TPN was 4.3 years. After 4 weeks of therapy, 26 (58%) were free of TPN support. Predictors of a favorable response included greater bowel length, lower body weight, and greater bowel length-body weight ratio. At follow-up, the percentage of patients who were not receiving TPN had fallen to 40%.

CONCLUSIONS

Approximately half of a group of patients, thought to have absorptive surface area inadequate to be independent of TPN support, can maintain themselves on enteral feedings after this intestinal rehabilitation program. Because of the risk, costs, and alterations in lifestyle associated with long-term TPN or intestinal transplantation or both, it seems prudent to consider a program of bowel rehabilitation with an individual patient before embarking on another therapeutic plan.

Determination of the route of medium-chain and long-chain fatty acid absorption by direct measurement in the rat

BACKGROUND

Medium-chain triglycerides are used for the treatment of malabsorptive states. We measured directly the absorption of medium- and long-chain fatty acids via the mesenteric lymphatics and portal vein in normal animals. These results may be useful in guiding therapy for short-bowel syndrome.

METHODS

Under anesthesia, male Lewis rats (n = 6) underwent placement of jugular and portal venous lines, mesenteric lymphatic duct cannula, and a duodenal tube. After recovery, a 0.3% lauric acid (C12:0) and 0.37% palmitic acid (C16:0) solution solublized with 3.25 mmol/L lecithin and 23.75 mmol/L taurocholic acid in phosphate-buffered saline was infused at a rate of 3 mL/h via the duodenal tube. After stabilization of lymphatic flow (6 hours), a pulse of radiolabeled lauric and palmitic acid was given via the duodenal tube; absorption was measured by collection of lymphatic fluid and sampling of the portal and jugular venous blood for 4 hours.

RESULTS

The amount of acid recovered in the lymphatics was 51% +/- 6% (mean +/- SD) for lauric and 59% +/- 6% for palmitic. For both fatty acids, < 1% in total was recovered from the portal vein during the 4-hour postbolus period; thereafter, levels in the blood were constant and very low. At necropsy, the majority of the remaining label was found in the intestine.

CONCLUSIONS

These results show no evidence for the preferential absorption of medium-chain fatty acids directly via the portal vein in this model. We suggest that further studies be done to measure directly portal vein absorption of the medium-chain fatty acids.

Human growth hormone induces system B transport in short bowel syndrome

BACKGROUND

After massive enterectomy, remnant intestine undergoes compensatory adaptation. A combination of human growth hormone (hGH) and a glutamine-enriched modified diet induces further adaptation in patients with short bowel syndrome (SBS) on long-term total parenteral nutrition. The specific actions of each component, however, are not well-defined.

METHODS

New Zealand White rabbits were randomized to control, sham operation, or SBS (70% midjejunoileal resection) groups and treated with either hGH or saline. Sodium-dependent uptake of glucose, glutamine, alanine, leucine, and arginine into brush border membrane vesicles was quantitated. Serum insulin-like growth factor-I (IGF-I) levels were determined by immunoradiometric assay. Mucosal mRNA expression of IGF-I and IGF binding protein 4 (IGFBP-4) was evaluated by northern blot analysis using rat cDNA probes.

RESULTS

Glutamine and leucine transports were 33 and 39% greater, respectively, in the hGH-treated versus saline-treated SBS group (P < 0.05), supporting induction of system B amino acid transport. This upregulation was due, in part, to an 88% increase in glutamine carrier capacity (Vmax) with no change in carrier affinity (Km). Both hGH treatment and SBS increased serum IGF-I levels without direct correlation with increased nutrient transport. IGFBP-4 mRNA expression in small bowel mucosa of saline-treated SBS animals was significantly greater than saline-treated unoperated control values. Mucosal IGFBP-4 mRNA was not significantly altered from control in the other study groups. IGF-I mRNA expression was not detected in mucosa, but weak hybridization was noted in rabbit liver.

CONCLUSIONS

Human growth hormone accelerates early adaptation in SBS by upregulation of system B carrier capacity. Serum IGF-I levels and mucosal IGF-I and IGFBP-4 mRNA expression did not directly correlate with this enhanced nutrient transport, suggesting that hGH might exert its adaptive effects by mechanisms that are independent from the IGF system in this model.

Octreotide diminishes luminal nutrient transport activity, which is reversed by epidermal growth factor

BACKGROUND

Octreotide (SMS) is a somatostatin analogue utilized in patients with short bowel syndrome (SBS) to decrease output. It may inhibit small bowel adaptation by blocking the secretion of trophic hormones such as epidermal growth factor (EGF). This study delineates the effects of SMS and EGF on nutrient transport in SBS.

METHODS

One week after 70% jejunoileal resection, 20 New Zealand White rabbits (2 kg) received subcutaneous infusions of saline or EGF (1.5 micrograms/kg/hr) and injections of saline or SMS s.q.b.i.d. The study groups were EGF/saline, saline/saline, saline/SMS, and EGF/SMS. After 7 days of infusion, intestinal brush border membrane vesicles were prepared and nutrient transport measured.

RESULTS

SMS reduced active nutrient transport. Kinetics confirmed this was secondary to a reduction in functional carriers in the brush border membrane, without a change in carrier affinity. The coinfusion of EGF ameliorated this effect. On an individual basis, EGF alone did not significantly increase nutrient transport, but when taken as a group, nutrients transport was upregulated 26%.

CONCLUSIONS

SMS is detrimental to small bowel adaptation. EGF reverses this effect and may benefit patients with SBS who require SMS to control high intestinal output.

Short-chain fatty acids increase proglucagon and ornithine decarboxylase messenger RNAs after intestinal resection in rats

BACKGROUND

Intestinal adaptation is a complex physiological process that is not completely understood. Systemic administration of short-chain fatty acids (SCFAs) has been shown to facilitate adaptation to small bowel resection; however the mechanisms underlying this phenomena are unknown.

METHODS

Forty-six male Sprague-Dawley rats underwent an 80% jejunoileal resection and jugular catheterization. After surgery, rats were randomly assigned to receive standard total parenteral nutrition (TPN) or an isoenergetic, isonitrogenous TPN supplemented with SCFAs. On day 3 or 7 after surgery, ileal samples were removed for determination of mucosal wet weight, DNA, RNA, and protein concentrations. Total cellular RNA was extracted for use in Northern blot analysis to quantify proglucagon and ornithine decarboxylase messenger RNAs (mRNAs).

RESULTS

Total, mucosal, and submucosal weights were increased (p < .05) in the SCFA group both 3 and 7 days after surgery. Ileal DNA and RNA concentrations were increased (p < .05) in the SCFA group at both time points; however ileal protein concentration did not differ between groups until 7 days after resection. Levels of proglucagon and ornithine decarboxylase messenger RNAs were higher (p < .05) in the SCFA group at both time points.

CONCLUSION

The upregulation of proglucagon and ornithine decarboxylase gene expression may be the mechanism by which SCFAs facilitate intestinal adaptation.

Sequential alterations in gut mucosal amino acid and glucose transport after 70% small bowel resection

BACKGROUND

Studies in animals with short bowel syndrome (SBS) suggest that up-regulation of nutrient transporter activity occurs as an adaptive response to the loss of absorptive area. It is unclear, however, whether nutrient transport is altered at the cell membrane in SBS. The purpose of this study is to clarify amino acid and glucose transport in small intestinal luminal mucosa after 70% small bowel resection in rabbits.

METHODS

New Zealand white rabbits underwent 70% jejunoileal resection (n = 27) or a sham operation (n = 19). Brush border membrane vesicles were prepared from small intestinal mucosa at 1 week, 1 month, and 3 months by magnesium aggregation-differential centrifugation. Transport of L-glutamine, L-alanine, L-leucine, L-arginine, and D-glucose was assayed by a rapid mixing-filtration technique.

RESULTS

We observed no difference in uptake of all amino acids and glucose at 1 week. The uptake of amino acids and glucose was decreased by 20% to 80% in animals with SBS at 1 month. By 3 months all uptake values except that of glucose returned to normal. Kinetic studies of the system B transporter for glutamine indicate that the decrease in uptake at 1 month was caused by a reduction in the Vmax (1575 +/- 146 versus 2366 +/- 235, p < 0.05) consistent with a decrease in the number of functional carriers on the brush border membrane.

CONCLUSIONS

In addition to the anatomic loss of absorptive area after massive bowel resection, alterations in enterocyte transport function may be responsible for malabsorption in patients with SBS.

Is enteral nutrition optimally used in hospitalized patients?A study of the practice of nutrition in a Swedish hospital

Thirty patients with parenteral nutrition were studied in order to evaluate if they could be given enteral nutrition instead. Based upon absolute and relative contraindications for enteral nutrition, we calculated that 80% of the patients were possible candidates for enteral nutrition. Long-term use of parenteral nutrition may cause complications. Besides metabolic and other advantages when enteral nutrition is used, economical gains are also important. We have calculated an estimated annual net profit of US$ 357,000 in our hospital, if enteral instead of parenteral feeding is used in patients suitable for the former type of feeding. This implies that it is really cost-beneficial to consider enteral nutrition in hospitalized patients. Although parenteral nutrition will continue to have its place in the management of different occasions, increased use of enteral nutrition may result in improved patient outcomes and improved cost-effectiveness.

Clinical intestinal transplantation

The advent of tacrolimus allowed clinical intestinal transplantation to become a feasible procedure for patients with irreversible intestinal failure. Over last 5 years, 71 patients underwent intestinal transplantation. Forty-one recipients were children, and 30 recipients were adults. Twenty-five patients received an isolated intestinal graft, 34 patients received a combined liver-intestinal graft, and 12 received a multivisceral graft. The colon was included the intestinal graft in 29 patients. One-year, 2-year, and 4-year actuarial patient survival is 72%, 57%, and 45%, respectively. Our experience has shown that infectious, and immunological problems have caused significant morbidity and mortality. In this paper, we present our clinical experience and overview with intestinal transplantation.

Intradialytic parenteral nutrition after small bowel resection

Malnutrition is frequently observed in the hemodialysis patient population. It may be associated with increased morbidity and mortality as well as affect overall quality of life, which may already be compromised from dialytic physical and psychological demands. In the past, intradialytic parenteral nutrition (IDPN) has been available to hemodialysis patients as an adjunct to their dietary intake. In this time of cost containment and the increasing need to scientifically justify the benefit of such therapies to have them paid for by third party reimbursers, IDPN is coming under much scrutiny. This report describes a case of inadequate enteral nutrient absorption in a malnourished hemodialysis patient. This is a case in which IDPN was beneficial and without which other alternatives would have proven more costly physically, emotionally, and economically to the patient.

A new treatment for patients with short-bowel syndrome. Growth hormone, glutamine, and a modified diet

OBJECTIVE

The purpose of this study was to initially determine if growth hormone or nutrients, given alone or together, could enhance absorption from the remnant small bowel after massive intestinal resection. If clinical improvement were observed, this therapy would then be used to treat patients with the short-bowel syndrome over the long term.

SUMMARY BACKGROUND DATA

Patients who undergo extensive resection of the gastrointestinal tract frequently develop malabsorption and require long-term parenteral nutrition. The authors hypothesized that the administration of growth factors and/or nutrients could enhance further compensation of the remnant intestine and thereby improve absorption. Specifically, animal studies have shown that there is enhanced cellularity with the administration of growth hormone (GH) or glutamine (GLN), or a fiber-containing diet.

METHODS

Initially, 17 studies were performed in 15 total parenteral nutrition (TPN)-dependent short-bowel patients over 3 to 4 weeks in the clinical research center; the first week served as a control period, and during the next 1 to 3 weeks, the specific treatment was administered and evaluated. Throughout the study, food of known composition was provided and all stool was collected and analyzed to determine absorption across the remaining bowel. The effect of a high-carbohydrate, low-fat diet (DIET), the amino acid glutamine (GLN) and growth hormone (GH) administered alone or in combination with the other therapies (GH + GLN + DIET) was evaluated. The treatment was expanded to 47 adults (25 men, 22 women) with the short-bowel syndrome, dependent on TPN for 6 +/- 1 years. The average age was 46 +/- 2 years, and the average jejunal-ileal length was 50 +/- 7 cm (median 35 cm) in those with all or a portion of colon and 102 +/- 24 cm (median 102 cm) in those with no colon. After 28 days of therapy, the patients were discharged on only GLN + DIET.

RESULTS

The initial balance studies indicated improvement in absorption of protein by 39% accompanied by a 33% decrease in stool output with the GH + GLN + DIET. In the long-term study, 40% of the group remain off TPN and an additional 40% have reduced their TPN requirements, with follow-up averaging a year and the longest being over 5 years.

CONCLUSION

GH + GLN + DIET offers a potential method for providing cost-effective rehabilitation of surgical patients who have the short-bowel syndrome or other complex problems of the gastrointestinal tract. This therapeutic combination also may be useful to enhance bowel function in patients with other gastrointestinal diseases and those requiring extensive intestinal operations, including transplantation.

Gut failure in pediatric and adult patients. Candidates for small-bowel transplantation in southern Finland

BACKGROUND

This study investigated the need for small-bowel transplantation (SBT) in southern Finland. In addition, we evaluated the effect of colon resection on the time required for intestinal adaptation in patients with gut failure.

METHODS

Mortality, morbidity, intestinal adaptation time, and surgical management were evaluated retrospectively in 24 patients (12 adults and 12 children) with jejunoileal exculsion. Of the 24 patients 19 had undergone accompanying colon resection.

RESULTS

Intestinal adaptation had occurred in 12 of 18 survivors (67%). Two unadapted survivors were considered to be currently suitable candidates for SBT. The length of the remaining colon was inversely correlated (correlation coefficient r = -0.789; p < 0.0001) with the duration of intestinal adaptation.

CONCLUSIONS

Each year one to two patients per 1.27 million people could benefit from SBT in southern Finland. The length of the remaining colon is a major determinant of the duration of intestinal adaptation in patients with massive jejunoileal resection.

Growth hormone, glutamine, and a modified diet enhance nutrient absorption in patients with severe short bowel syndrome

BACKGROUND

Massive loss of intestinal surface area results in the short bowel syndrome characterized by malabsorption of fluid, electrolytes, and other nutrients. Although the remaining bowel undergoes morphological and functional adaptation, often these changes are inadequate to support the individual by enteral feedings, and parenteral nutrition is required to prevent dehydration, electrolyte disturbances, and malnutrition. Substances such as growth hormone, glutamine, and fiber exert bowel-specific trophic effects and either directly or indirectly influence nutrient absorption. This study was undertaken to determine whether the co-administration of exogenous growth hormone, supplemental glutamine, and a modified fiber-containing diet could enhance nutrient absorption in patients who had undergone massive intestinal resection.

METHODS

Ten patients (5 men, 5 women, aged 43 +/- 4 years) with short bowel syndrome were studied 6 +/- 1 years after surgical resection. All patients were admitted to the Clinical Research Center for a 28-day period; the first week served as a control period when nutritional (enteral and parenteral) and medical management simulated usual home therapy. Thereafter, eight patients received exogenous growth hormone, supplemental glutamine, and a modified high-carbohydrate, high-fiber diet. Two patients were treated with the modified diet alone. The efficiency of net nutrient absorption (percent absorbed) for total calories, protein, fat, carbohydrate, water, and sodium was calculated from the measured nutrient intake and stool losses.

RESULTS

Three weeks of treatment with growth hormone, glutamine, and a modified diet increased total caloric absorption from 60.1 +/- 6.0% to 74.3 +/- 5.0% (p < or = .003), protein absorption from 48.8 +/- 4.8% to 63.0 +/- 5.4% (p < or = .006), and carbohydrate absorption from 60.0 +/- 9.8% to 81.5 +/- 5.3% (p < or = .02). Fat absorption did not change (61.0 +/- 5.3% to 60.3 +/- 7.9%, p = NS). Water and sodium absorption increased from 45.7 +/- 6.7% to 65.0 +/- 7.3% (p < or = .002) and from 49.0 +/- 9.8% to 69.6 +/- 6.5% (p < or = .04), respectively. These absorptive changes resulted in a decrease in stool output (1,783 +/- 414 g/d control period vs 1,308 +/- 404 g/d third week of treatment, p < or = .05). Treatment with diet alone did not influence nutrient absorption or stool output.

CONCLUSIONS

The combined administration of growth hormone, glutamine, and a modified diet enhanced nutrient absorption from the remnant bowel after massive intestinal resection. These changes occurred in a group of patients that had previously failed to adapt to the provision of enteral nutrients. This therapy may offer an alternative to long-term dependence on total parenteral nutrition for patients with severe short bowel syndrome.

Surgical treatment of inflammatory bowel disease

Surgery continues to play an important role in the overall treatment strategy for patients with Crohn's disease and ulcerative colitis. Innovative techniques have greatly facilitated the operative approach in patients with both disorders.

Design and fabrication of biodegradable polymer devices to engineer tubular tissues

Engineering new tissues by transplanting cells on polymeric delivery devices is one approach to alleviate the vast shortage of donor tissue. However, it will be necessary to fabricate cell delivery devices that deliver cells to a given location and promote the formation of specific tissue structures from the transplanted cells and the host tissue. This report describes the design and fabrication of a polymeric device for guiding the development of tubular vascularized tissues, which may be useful for engineering a variety of tissues including intestine, blood vessels, tracheas, and ureters. Porous films of poly (D, L-lactic-co-glycolic acid) have been formed and fabricated into tubes capable of resisting compressional forces in vitro and in vivo. These devices promote the ingrowth of fibrovascular tissue following implantation into recipient animals, resulting in a vascularized, tubular tissue. To investigate the utility of these devices as cell delivery devices, enterocytes (intestinal epithelial cells) were seeded onto the devices in vitro. Enterocytes were found to attach to these devices and form an organized epithelial cell layer. These results suggest that these devices may be an appropriate delivery vehicle for transplanting cells and engineering new tubular tissues.

The current role of small-bowel transplantation in intestinal failure

Short bowel syndrome is the clinical manifestation of a fundamental reduction in the functional intestinal absorptive surface area and malabsorption. The development of total parenteral nutrition has improved the natural course of this disease. Home parenteral nutrition-related complications continue to generate significant morbidity and mortality for these patients. Small-bowel transplantation is an alternative to home parenteral nutrition. There are significant risks of graft rejection and the potential complications of long-term immunosuppression. Small-bowel transplantation is an option, but it should be reserved for patients no longer considered candidates for continued home parenteral nutrition.

The role of home parenteral nutrition in the management of intestinal failure — report of 400 cases

Between 1977 and January 1991, 400 patients were entered on the United Kingdom Home Parenteral Nutrition (HPN) Register. Almost half suffered from Crohn's disease. Most commenced HPN while between 20-50 years of age. In terms of life quality while on HPN, most (63%) were able to work or look after their families unaided. A further 89 (22%) were able to cope with HPN independently. 221 patients ceased HPN during the study period, mostly (41%) due to intestinal adaptation. Of 69 patients who died, over half (57%) did so due to disease progression. Complications of HPN resulted in death in 22% of this subgroup. In terms of specific disease groups, those with Crohn's disease had the lowest mortality rate (8%).